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Letter
Multidrug-Resistant Shigella
dysenteriae Type 1: Forerunners of a New Epidemic Strain in Eastern
India?
Dipika Sur,* Swapan K. Niyogi,* Shravani Sur,† Kamal K. Datta,* Yoshifumi
Takeda,‡ Gopinath Balakrish Nair,§ and Sujit K. Bhattacharya*
*National Institute of Cholera and Enteric Diseases, Kolkata, India; †Burdwan
Medical College, Burdwan, West Bengal; ‡Jissen Women’s University, Tokyo,
Japan; and §International Centre for Diarrhoeal Diseases Research, Dhaka,
Bangladesh
Suggested citation for this article: Sur D, Niyogi
SK, Sur S, Datta KK, Takeda Y, Nair GB, et al. Multidrug-resistant Shigella
dysenteriae type 1: forerunners of a new epidemic strain in eastern
India? Emerg Infect Dis [serial online] 2003 Mar [date cited].
Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no3/02-0352.htm
To the Editor: Multidrug-resistant Shigella dysenteriae
type 1 caused an extensive epidemic of shigellosis in eastern India in
1984 (1). These strains were, however, sensitive to nalidixic
acid, and clinicians found excellent results by using it to treat bacillary
dysentery cases. Subsequently, in 1988 in Tripura, an eastern Indian state,
a similar outbreak of shigellosis occurred in which the isolated strains
of S. dysenteriae type 1 were even resistant to nalidixic acid
(2). Since then, few cases of shigellosis have occurred
in this region, and S. dysenteriae type 1 strains are scarcely
encountered (3). In other regions of the world, especially
in Southeast Asia, low-level resistance to fluoroquinolones in Shigella
spp. has been observed for some time (4,5).
After a lapse of almost 14 years, clusters of patients with acute bacillary
dysentery were seen at the subdivisional hospital, Diamond Harbour, in
eastern India. No cases of dysentery had been reported during the comparable
period in previous years. A total of 1,124 case-patients were admitted
from March through June 2002. The startling feature of these infections
was their unresponsiveness to even the newer fluoroquinolones such as
norfloxacin and ciprofloxacin, the drugs often used to treat shigellosis.
Clinicians tried various antibiotics, mostly in combinations, without
benefit. Clinicians also randomly used anti-amoebic drugs without success.
An investigating team collected nine fresh fecal samples from dysentery
patients admitted to this hospital; 4 (44%) yielded S. dysenteriae
type 1 on culture. For isolation of Shigella spp., stool samples
were inoculated into MacConkey agar and Hektoen Enteric agar (Difco, Detroit,
MI), and the characteristic colonies were identified by standard biochemical
methods (6). Subsequently, serogroups and serotypes were
determined by visual inspection of slide agglutination tests with commercial
antisera (Denka Seiken, Tokyo). Antimicrobial susceptibility testing was
performed by an agar diffusion disk method, as recommended by the National
Committee for Clinical Laboratory Standards (7). Results
showed that the organisms were resistant to all commonly used antibiotics,
including the fluoroquinolones (norfloxacin and ciprofloxacin) but were
sensitive to ofloxacin. On our advice, the clinicians used ofloxacin with
good results.
A similar outbreak of S. dysenteriae type 1 occurred in the northern
part of West Bengal in eastern India among tea garden laborers from April
2002 to May 2002; 1,728 persons were affected (attack rate of 25.6%).
Sixteen persons died. The isolated S. dysenteriae type 1 strains
were found intermediately sensitive to fluroquinolones with an MIC of
2 µg/mL (K. Sarkar, S. Ghosh, S.K. Niyogi, S.K. Bhattacharya, pers.
commun.).
This drug-resistant Shiga bacillus is highly likely to spread further
and will certainly pose a major therapeutic challenge unless adequate
preventive measures are immediately instituted to contain its spread.
Appropriate awareness programs for the community and reorientation training
for physicians and other health personnel would be helpful to prevent
further transmission of these resistant organisms. Alternative drugs to
treat drug-resistant cases and an effective vaccine are also needed.
References
- Pal SC. Epidemic
bacillary dysentery in West Bengal. Lancet 1984;1:1462.
- Sen D, Dutta P, Deb BC, Pal SC. Nalidixic
acid resistant Shigella dysenteriae type 1 in eastern India.
Lancet 1988;2:911.
- Niyogi SK, Mitra U, Dutta P. Changing
pattern of serotypes and antimicrobial susceptibility of Shigella
species isolated from children in Calcutta, India. Jpn J Infect
Dis 2001;54:121–2.
- Anh NT, Cam PD, Dalsgaard A. Antimicrobial
resistance of Shigella spp. isolated from diarrhoeal patients
between 1989 and 1998 in Vietnam. Southeast Asian J Trop Med Public
Health 2001;32:856–62.
- Nguyen JC, Goldstein FW. Low
level resistance to fluoroquinolones among Salmonella and Shigella.
Clin Microbiol Infect 2000;6:231.
- World Health Organization. Manual for laboratory investigations of
acute enteric infections. Document WHO/CDD/83.3. Geneva: the Organization;
1983.
- National Committee for Clinical Laboratory Standards. 1997: Performance
standard for antimicrobial disk susceptibility tests: approved standards.
6th ed. NCCLS document M2-A6, Wayne (PA): The Committee; 1997.
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